| 摘要 |
PROBLEM TO BE SOLVED: To prevent the adhesion of scales in a polymerizing device in the production of a synthetic resin by subjecting the surface of a metal essentially consisting of stainless steel or iron to heating treatment at a temp. equal to or above the specified one with an aq. soln. of alkali metal hydroxide or a mixed soln. of the pH equal to or above the specified one obtd. by mixing an aq. soln. of alkali metal hydroxide with an organic solvent and forming a coating film. SOLUTION: The pH of the mixed soln. is >=8, and the heating treating temp. is >=50 deg.C. As the surface treating soln., the one added with an organic solvent is more desirable, and a uniform coating film can be obtd. with alkali metal hydroxide of low concn. The weight ratio between the non-water soluble liq. and the hydroxide of alkali metal is preferably controlled to 100: (0.1 to 5.0). In the case heating treatment is executed at 100 to 150 deg.C while it is brought into contact with the non-water soluble solvent in succession to the surface treatment, the function of preventing the adhesion of scales furthermore improves. The adhesion of scales to a polymer can be prevented over a long period, and the intrusion of gels is less as well. It is suitable for the production of a synthetic resin from a monomer contd. unsaturated nitrile and aromatic vinyl.
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